Combustion analysis apparatus



p 1952 G. M. DREHER COMBUSTION ANALYSIS APPARATUS Filed Jan. 17, 1950INVENTOR QEaRaE M. DREHER VB 1 Y M Mf ATTO RN Patented Sept. 9, 1952@171 UNITED STATES PATENT OFFICE l r i 2,r1o,107 I COMBUSTION ANALYSISAPPAn 'r s George M. Drcher, Pittsburgh, Pa.

Application January 17, 1950, SerialNo.139,045

My invention relates in general to combustion apparatus for use inchemical analysisand in particular to a novel combustion tube which maybe used in the determination of the carbon and sulphurjcontent of ironor steel.

As part of the apparatus usedin making such determinationit is customaryto employ a combustion tube of suitable refractory material, inside ofwhich tube, one or more refractory liners areplaced and inside one ofthe liners a boat of refractory material containing the sampleto beanalyzed is positioned. The tube is located with a portion thereofinside a heating furnace which may be aigas furnace or an electricfurnace.

V In determining carbon and sulphur content of a sample of iron orsteel, it is customary to place the sample 'in a boat made fromrefractory material, which boat is placed inside a liner of refractorymaterial, and the boat and liner are placedinside a combustion tube. Theassembly is placed ina suitable furnace so that a portion of theassembly may be heated to a temperature say'of theorder of 2500 F.',while a. suitable gas, usually oxygen, is passedthro'ugh the assemblyand over the sample and into the determination apparatus.

Heretofore ithas been the practice to us a combustion tube of uniformdiameter throughout, or for at least the major portion of its length.When an uncovered boat is used, it is good economy to protect the tubeby, also using a liner which extends along the boat and is long enoughtocover the boat, and small enough in diameter to be readily inserted inand withdrawn from the tube. The liner protects the tube from spatteringslag, and when sufficientslag or other foreign. material collects onitsinternal surface, it may be replaced.

,The main purpose of this invention is to provide a combustion tube ofimproved construction which is particularly adapted to the use of areplaceable liner. To this end, the portion of the tube which ispositioned within the furnace is.

provided with a depression in its lower internal surface in which acylindrical liner may be placed. The depression has shoulders at itsends which are spaced apart a distance slightly greater than the lengthof the liner and which thus act to hold the liner in position to preventaccidental displacement of the liner in the tube. In a manner which willbe described, the liner has a wall thickness substantially the same asthe depth of the depression so that its internal surface constitutes acontinuation of the internal surface of the inlet 4 Claims. (01. 23-253)end portion of the tube whereby a combustion boat may slide freely toand from a position within the liner. The liner thus need be moved orreplaced only when suflicient dirt has accumulated I on its interiorsurface as will interfere with move- It is another object of myinvention to provide a combustion analysis tube which has a boatwhichhas a shaped bottomto correspond with the inner wall of the linerin which it is placed.

It is stillanoth'er object of my invention'to provide a combustionanalysis apparatus of such proportions that the volume of gasemployed'is a convenient minimum.

It is a further object to provide a combustionanalysis appara'tusinwhich the tube, the liner and the boat are so proportioned that thevarious needed manipulative steps may be performed and the tube soproportioned asto permit the use of a relatively low volume of gas.

It is a still further object to provide a combustion analysis apparatuswhich is simple, inexpensive, accurate, and which will enable relativelylow cost determination of the chemical constituents of a material sampleto be mad by combustion analysis.

1 In the accompanying drawings, wherein I have shown the presentlypreferred embodiments of my invention:

Figure 1 is a view in vertical section of a conventional heating furnaceshowing my improved tube,liner and boat assembly in operative posi: tionin the furnace;

Figure 2 is an enlarged vertical sectional view of the apparatus alongthe line 11-11 of Figure 1;

Figure 3 is an enlarged vertical sectional view along line III-III ofFigure l; and

Figure 4 is an, enlarged vertical sectional view along line IV-IV ofFigure 1.

In the drawings, the reference numeral I0 designates a combustionfurnace of known construction having a combustion chamber ll surroundedby insulating walls I! of any suitable refractory material. A combustiontube H formed of any suitable refractory material, passes horizontallythrough the end walls of the furnace and through the heating orcombustion chamber II. The tube 14 extends for a desir able distancebeyond the end walls to provide at one end an inlet end l6, and at theother end a discharge portion or exit end Between the tube end portionsthere is a bulge or an enlarged portion N3 of greater cross sectionaldepth than is the inlet portion l6, which in turn is of a cross sectiongreater than that of exit portion IT.

The upper wall of inlet portion I6 and enlarged portion iii are in thesame plane, while the lower portion offthe inner wall of enlargedportion I8 is in a plane below that of the lower portion of the innerwall of inlet portion l6, when the tube is in a horizontal position. Theright-hand end of the bottom of the enlarged portion or bulge I8 isconnected to the bottom of the-inlet portion I8 by a shoulder 20 whichextends part way round the junction of the portions as seen in Figure 3.The difference in levels of the bot- Y toms of the inner walls issubstantally equal to the thickness of asrefractoryliner- 2|;which isshown in operatingxposition in the shell of the enlarged portion I8.

The exit portion ll of. the combustion tube is of asection less'thanthat of the enlarged por-; tion I8, and forms at the junction withportion I8, an annular shoulder 22. There is; thus pro.- videda centralportion l8 which is larger in diameter than is the inlet portion, I6 andstill larger than is the exit portion As representative dimensions, theinlet portion l6 mayhavean inner diameter of about /4 of an inch, whilethe exit portionmay have an inner diameter of about inch to, about '7inch. The liner 2| may be conveniently about 4," long, of cylindricalform, with an outside-diameter of about of an inch and a uniform wallthickness of the order of about of an inch. The inner diameter of theenlarged portion l8 could well be. of the order of to inch, and thelengthof about ll/g-inches long enough to receive the liner 2The'various dimensions are such, that. the, liner may be. moved throughthe inlet portion IE to the chemical determination position, in theenlarged center portion |8'. When the liner is placed in positionbetween the shoulders and 22, it will remain there until it is purposelymoved by means of a manipulative device, such as a hooked wire. Theshoulders 20 and, 22 prevent accidental displacement.

The dimensions I have set forth are those of a desirable apparatus. Butthe measurements are exemplary only, and the dimensions adopted .may bemore'or less as the operator desires and convenience necessitates.

I place in the liner 2| a boat 25 which I prefer to make with a'bottomportion 26 shaped so as to conform to the lower portion of the innerwall of the liner. The boat has straight sides 24, and which extend to aposition close to the side walls of the liner, and the ends are slopedoutwardly and upwardly as shown in Figure'l. A handle 21 with an eye 28therethrough extends to the right as shown in Figure 1. By means of ahooked wire which may be connected to this eye, the boat 25 may be movedinto or out of its position inside the liner 2|, which is located whenin operation in the enlarged portion Hi.

In the determination operation, the boat 25 with its chemical samplemust bermoyed along the lower wall of .the inlet portion. and into'p0-'sition in the liner as shown in Figure 1. For this purpose it is highlydesirable that the bottom portion of the inner wall of the liner 2|.should be-at least as low and. preferably slightly:

from the liner in position in the enlarged portion l8 without dimculty.The height of the walls of the boat should be such as'can be readilyinserted in the liner, and it must be remembered that the dimensions ofthe various portions of the 'appa'ratusmust be such'as v'villmakeallowance for the variations in the finished dimensions of the variousrefractory articles comprising the apparatus, which by the nature oftheir manufacture, cannot be assuredly held to precise measurements.

In operation, the tube M is mounted in position within the furnace asillustrated in Fig. l.

A liner 2| is then placed in position within the enlarged portion |8 ofthe tube M with its ends positioned between the shoulders 20 and 22 atthe ends of the enlarged portion |'8 so that such shoulders'operate toprevent accidental endwise movementof the liner 2 The furnace maythen.be --operated to bring the portion of the tube within the furnace andits liner 2| up to operating temperature. The combustionboatlii may thenbe slid over the bottom surfaces of the in.- let end portion I6 of thetube and'liner- 2| to aposition within the liner 2|. The lower internalsurface of the liner 2| being in substantially the same plane as thelower internal surface of the tube IS, the insertion. and removal of theboat 25 may be effected without diniculty. The liner, of course, needbev placed only when sufficient slag has collected on its internalsurfaceto interfere with the flow of oxygen through the liner or theremoval and replacement of the combustion boat; The dimensions oftheparts', particularly the size.

of the enlarged portion 8 with respect. to the in.- let end, portion l6and the outlet end portion I1 and the formation of the end l! with asmaller diameter than the inlet end it, is, particularly designed? tomaintain the, internal, volume of the. tube at a minimumwhilefacilitating the removal and replacement of both the liner 2| and thecombustion tube25.

While I have described the presently preferred embodiment of myinvention, it is to be known that changes and, modifications. may bemade within the scope of the following claims.

I claim:

1. In combustion analysis apparatus including having inlet and outletend portions extending through said walls and a center portion posi--tioned in said chamben'said centerportlon having on its lower internalsurface a depression providing shoulders spaced from each other axiallyof the tube, and a cylindrical protective liner having a length slightlyless than the spacing of said shoulders for insertion in said tube to aposition in which said shoulders act as abutments for preventing axialdisplacemet of the liner out of said depression, said liner having awall thickness and said depression having a depth-which aresubstantially equal so'that the bottom internal surface of said linerin'efl'ect constitutes a continuation of the bottom internal surfacev ofone of said end portions whereby a' I 2. The invention described inclaim 1 charac terized by said central portion, having a diameter.

greater than either of said end portions to facilitate removal of saidliner from said central portion.

3. The invention described in claim 2 characterized by said one endportion being the inlet portion, and said outlet portion having adiameter less than the diameter of said outlet portion to thereby reducethe space in said tube to a minimum.

4. In combustion analysis apparatus including a heating furnace havinginsulated walls defining a heating chamber therein, a combustion tubehaving inlet and outlet end portions extending through said walls and acenter portion positioned in said chamber, said center portion havingthe bottom portion of its internal surface depressed below the level ofthe bottom portion of the internal surface of said inlet end portion toprovide a shoulder between said internal surfaces, an abutment at theother end of said depressed center portion and a cylindrical linerhaving a (length slightly less than the distance between said shoulderand abutment for insertion in said tube to a position lying on saiddepressed center portion, said liner having a thickness and saiddepressed center portion having a depth which are substantially equal sothat the bottom internal surface of said liner constitutes acontinuation of the bottom internal surface or said inlet end portionwhereby a combustion boat may slide freely over said internal surfacesin its removal from and insertion in said liner.

GEORGE M. DREHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Yensen Nov. 11, 1924 Dreher Aug. 14,1945 Number

1. IN COMBUSTION ANALYSIS APPARATUS INCLUDING A HEATING FURNACE HAVINGINSULATED WALLS DEFINING A HEATING CHAMBER THEREIN, A COMBUSTION TUBEHAVING INLET AND OUTLET END PORTIONS EXTENDING THROUGH SAID WALLS AND ACENTER PORTION POSITIONED IN SAID CHAMBER, SAID CENTER PORTON HAVING ONITS LOWER INTERNAL SURFACE A DEPRESSION PROVIDING SHOULDERS SPACED FROMEACH OTHER AXIALLY OF THE TUBE, AND A CYLINDRICAL PROTECTIVE LINERHAVING A LENGTH SLIGHTLY LESS THAN THE SPACING OF SAID SHOULDERS FORINSERTION IN SAID TUBE TO A POSITION IN WHICH SAID SHOULDERS ACT ASABUTMENTS FOR PREVENTING AXIAL DISPLACEMET OF THE